Electrical panelboard having plug-in line and load connections to circuit breaker

ABSTRACT

The panelboard has flat bus bars stacked in a direction perpendicular to a mounting pan and is provided with plug-in load-side connectors. Circuit breakers having line-side jaws for plugging onto the bus bars by movement parallel to the mounting pan are provided with stab terminals for plugging into jaws of the connectors. Load wires are secured to terminals of the connectors and need not be disturbed when a circuit breaker is plugged into or removed from the panelboard.

United States Patent Inventor Wilhelm T. Hackenbroch [56] ReferencesCited A I N gear; Rapids, Iowa UNITED STATES PATENTS fif i 12 19703,404,315 10/1968 Jacobs 317/119 P 2,641,746 6/1953 Keller 339/191 19712 837 699 6/1958 F r 317/119 Assignee squlmncompany o e Park Ridge I"2,986,676 5/1961 Edmunds... 317/119 3,354,357 11/1967 Jorgensen 317/119Primary Examiner-Lewis H. Myers Assistant Examiner-Gerald P. TolinAttorneys-Harold J. Rathbun and Paul J. Rose ELECTRICAL PANELBOARDHAVING PLUG'IN ABSTRACT: The panelboard has flat bus bars stacked in aLINE AND LOAD CONNECTIONS T0 CIRCUIT I d d BREAKER |rect1on perpen 1cuar to a mounung pan an 1s prov1 e wlth lu -1n load-slde connectors.C1rcu1t breakers havln 9 Claims 10 Drawing FlgS. P g g line-side jawsfor plugging onto the bus bars by movement US. Cl 317/119, parallel tothe mounting pan are provided with stab terminals 317/112 for plugginginto jaws of the connectors. Load wires are Int. Cl 1102b l/04 securedto terminals of the connectors and need not be Field of Search 317/113,disturbed when a circuit breaker is plugged into or removed 118, 119;339/191, 192 from the panelboard.

3O rL 29 l 32 k 20 37 66 3 2 2 27- I 26 g s 8 1* w 5 i 81 M1 35 22b 3o16 1 1 w 11 11 PATENTEU 9 I97! I 3 8 1 9 7'2 7 SHEET 2 BF 2 FIG. 9 FIG.IO

INVENTOR. WILHELM T. HACKENBROCH ELECTRICAL PANELBOARD HAVING PLUG-INLINE AND LOAD CONNECTIONS 'IO CIRCUIT BREAKER This invention is animprovement on electrical panelboards of the type disclosed in U.S. Pat.Nos. 3,346,777 and 3,354,357, respectively issued Oct. 10 and Nov. 2 I1967.

An object of the invention is to provide an electrical panelboard andcircuit breaker combination in which circuit breakers can be pluggedinto or removed from an in-service panelboard without disturbance ofload wire connections.

Other objects and advantages will become apparent upon consideration ofthe following specification and drawings in which:

FIG. 1 is a transverse sectional view of an electrical panelboardconstructed in accordance with the invention, and including plug-inload-side connectors, the front trim panel and cover being omitted;

FIG. 2 is a view of a smaller one of the plug-in load-side connectors ofthe panelboard of FIG. 1, taken in the direction of arrows 2-2 of FIG.1, portions of a cover of the connector being removed; I

FIG. 3 is an end view of the connector of FIG. 2, taken in the directionof arrows 3-3;

FIG. 4 is a sectional view taken generally along the line 44 of FIG. 2and including a fragmentary sectional view of an electrical circuitbreaker plugged into the connector;

FIG. 5 is a fragmentary sectional view taken along the line 5-5 of FIG.2;

FIG. 6 is a fragmentary sectional view taken along the line 6-6 of FIG.2, but omitting the cover;

FIG. 7 is a view of a bracket secured to the circuit breaker of FIG. 4,taken in the direction of arrows 77 of FIG. 4;

FIG. 8 is a view of a larger one of the plug-in load-side connectors ofthe panelboard of FIG. 1, taken in the direction of arrows 8-8 of FIG.1, a portion of the cover being removed;

FIG. 9 is a sectional view taken along the line 9-9 of FIG. 8 andincluding a fragmentary sectional view of an electrical circuit breakerplugged into the connector; and

FIG. 10 is a fragmentary sectional view taken along the line 10--10ofFIG. 8.

FIG. 1 shows an electrical panelboard 20 including an openfront box 22and a generally flat mounting pan 24 secured to a rear wall portion 220of the box in any suitable manner.

As in the aforementioned U.S. Pat. Nos. 3,346,777 and 3,354,357, thepanelboard 20 includes three elongated flat bus bars 26 stacked flatwiseparallel to the mounting pan 24, separated from each other by a pair ofintermediate insulators 27, and disposed between a rear insulator 28 anda front insulator 29. The bus bars and insulators are clamped between apair of clamping members 30 by a plurality of longitudinally spacedbolts 31 and nuts 32, only one bolt 31 and one nut 32 being shown inFIG. 1. The general arrangement may be better understood by reference toFIGS. 2 and 3 of U.S. Pat. No. 3,354,357. However, in accordance withthis invention, the bus bars and insulators are clamped to a spacingchannel 34 secured to the mounting pan 24 in any suitable manner, ratherthan being clamped directly to the mounting pan 24 as in the aforesaidpatents.

Also in accordance with this invention, the panelboard 20 is providedwith a plurality of plug-in load-side connectors which may be ofdifferent sizes, a relatively small connector 35 and a relatively largeconnector 36 being shown in FIG. 1. There may be a row of connectors 35extending along the length of the bus bars 26 on one side of the spacingchannel 34 and a row of connectors 36 extending along the length of thebus bars 26 on the other side of the spacing channel 34, or the rows maybe mixed.

A relatively small three-pole molded-case circuit breaker 37 is pluggedat its line end onto the bus bars 26 and at its load end into theconnector 35. The basic mechanism of the circuit breaker 37 isessentially the same as that disclosed in U.S. Pat. No. 3,341,791,issued Sept. 12, 1967, the wire-receiving line terminals of thestructure of that patent being replaced in the circuit breaker 37 byplug-on jaws, as shown in the aforementioned U.S. Pat. No. 3,346,777,for plugging onto the bus bars 26, and the wire-receiving load terminalsof the structure of U.S. Pat. No. 3,341,791 being replaced in thecircuit breaker 37 by stab terminals 38, one of which is shown in FIG.4, for plugging into the connector 35. Thus, the circuit breaker 37 hasa generally rectangular molded case with three plug-on jaw line terminalmeans accessible from one end portion of the case and three plug-in loadterminal means 38 extending from a rear portion of the case adjacent theother end portion.

The connector 35 includes a base 39 and a generally flat cover 40 moldedof insulating material and secured together by four eyelets or hollowrivets 42. The base 39 has a hollow portion divided into threecompartments 39a, 39b and 39c by a pair of intermediate walls 39d and392. Each of the three compartments has a generally L-shaped terminalstrap 44 secured therein by a screw 45 countersunk in and extendingthrough a rear wall 39f of the base 39 and threaded through an openingin a longer leg portion of the terminal strap 44. A free end portion ofa shorter leg portion of each of the terminal straps 44 has a plug-injaw member 46 secured thereto by a screw 47 extending through the jawmember 46 and threaded into an opening in the terminal strap 44. A freeend portion of the longer leg portion of each of the terminal straps 44has a connector body 48 secured thereto by a screw (not shown)countersunk in and extending through an adjacent portion of theconnector body and threaded into an opening in the terminal strap 44.The ends of the compartments 39a, 39b and 390 adjacent the respectiveconnector bodies 48 are open, as shown in FIGS. 3 and 4 and eachconnector body 48 is provided with a through hole 48a for receiving aload wire (not shown) and a transverse threaded hole in which a clampingscrew 50 is mounted for clamping the load wire against a countersunkhead of the screw (not shown) securing the connector body to therespective terminal strap 44. (Note the similar arrangement in FIG. 9,hereinafter described, in which the screw securing the connector body tothe terminal strap is shown). If desired, an insulating wiring barrier(not shown) may be included in each of the compartments 39a, 39b, and39c adjacent the inner end of the hole 48a of the respective connectorbody 48.

The connector 35 is secured to the mounting pan 24 by a plurality ofmounting screws (not shown) extending respectively through the hollowrivets 42 and through bushings 52 (FIG. 3) provided respectively in aplurality of mounting foot portions 39g of the base 39 adjacent theinner ends of passageways 39h containing the hollow rivets 42.

Each pole of the three-pole circuit breaker 37 is provided with aterminal strap 54 (FIG. 4) to which the respective stab terminal 38 issecured by a screw 56 extending through a bushing 58 and threaded intothe stab terminal 38.

The cover 40 is provided with three slots 40a appropriately shaped forrespectively receiving the stab terminals 38 and for receiving a toolsuch as a screwdriver (not shown) to operate the clamping screws 50. Inthe installation of the circuit breaker 37 in the electrical panelboard20, the stab terminals 38 are first received in the plug-in load-sideconnector 35 perpendicularly to the rear wall 39f of the base 39respectively between the connector bodies 48 and the plug-in jaw members46, and are then moved parallel to the rear wall 39f into cooperativeengagement respectively with the jaw members 46.

A considerable amount of force is required to move the stab terminals 38into engagement respectively with the jaw members 46 at the same timethe line-side plug-on jaws (not shown), as disclosed in U.S. Pat. No.3,346,777, are plugged respectively onto the bus bars 26. For thisreason, a pair of rack members 60 (FIGS. 2 and 5) is provided in asuitable recess in the intermediate wall 39d of the base 39, a suitableaccess opening (not shown) being provided in the cover 40, and agenerally U-shaped bracket 62 (FIGS. 4 and 7) is secured to the rear ofthe circuit breaker 37 by rivets (not shown) extending through a pair ofholes 62a provided in opposed leg portions 62b and 62c of the bracket. Atool'receiving aperture 62d, for receiving a tool such as a screwdriver,is

provided in the bracket 62 adjacent the free end of the leg portion6212, which is longer than the leg portion 620. Thus, a screwdriver maybe used in conjunction with the bracket 62 and rack members 60 to prythe circuit breaker 37 into and out of cooperative engagement with thebus bars 26 and jaw members 46. The two rack members 60 may be made inone piece, but preferably two rack members, each of a thickness one-halfof their combined thickness, are provided for facility in stamping themfrom sheet steel.

Unintentional disengagement of the plug-on jaws (not shown) and the stabterminals 38 of the circuit breaker 37 respectively from the bus bars 26and the jaw members 46 may be prevented by a stop screw 64 mounted in anut 65 frictionally secured in a suitable recess in the intermediatewall 39s of the base 39. After the circuit breaker 37 is plugged in, thestop screw 64 may be turned outwardly, a suitable access hole beingprovided in the cover 40, until the outer end portion of the stop screwis aligned with free end portion of the leg portion 62c of the bracket62 so as to prevent disengagement of the circuit breaker 37.

A relatively large circuit breaker 66 is plugged at its line end ontothe bus bars 26 and at its load end into the plug-in loadside connector36. The basic mechanism of the circuit breaker 66 is essentially thesame as that disclosed in U.S. Pat. No. 3,355,685, issued Nov. 28, 1967,the wire-receiving line terminals of the structure of that patent beingreplaced in the circuit breaker 66 breaker 66 by plug-on jaws, as shownin the aforementioned U.S. Pat. No. 3,346,777, for plugging onto the busbars 26, and the wire-receiving load terminals of the structure of U.S.Pat. No. 3,355,685 being replaced in the circuit breaker 66 by stabterminals 68, one of which is shown in FIG. 9, for plugging into theconnector 36. Thus, the circuit breaker 66 has a generally rectangularmolded case with three plug-on jaw line terminal means accessible fromone end portion of the case and three plug-in load terminal means 68extending from a rear portion of the case adjacent the other endportion.

The connector 36 includes a base 69 and a cover 70 molded of insulatingmaterial and secured together by four eyelets or hollow rivets 72, oneof which is indicated in FIG. 8 and another of which is indicated inFIG. 10, in the same manner that the rivets 42 secure together the base39 and cover 40 (FIG. 3). The base 69 has a hollow portion divided intothree compartments by a pair of intermediate walls, one of which isindicated at 69a. Each of the three compartments has a generallyL-shaped terminal strap 74 secured therein by a pair of screws 75extending through a rear wall 69b of the base 69 and threaded through anopening in a longer leg portion of the terminal strap 74. A free endportion of a shorter leg portion of each of the tenninal straps 74 has aplug-in jaw member 76 secured thereto by a screw 77 extending throughthe jaw member 76 and threaded into an opening in the terminal strap 74.A free end portion of the longer leg portion of each of the terminalstraps 74 has a connector body 78 secured thereto by a screw 79countersunk in and extending through an adjacent portion of theconnector body and threaded into an opening in the tenninal strap 74.

Each connector body 78 is provided with a through hole 780 for receivinga load wire (not shown) and a transverse threaded hole in which a pairof clamping screws 80 is mounted for clamping the load wire against thehead of the screw 79.

Each jaw member 76 is provided with a spring member 81 to aid inmaintaining contact pressure on the respective stab terminal 68 of thecircuit breaker 66.

The cover 70 has a smaller cover 82 removably secured thereto by a pairof screws 83 threaded respectively into a pair of inserts 84 (FIG. thecover 82 being removed before tightening of the clamping screws 80 andreplaced thereafter.

The connector 36 is secured to the mounting pan 24 by a plurality ofmounting screws (not shown) extending respectively through the hollowrivets 72.

Each pole of the three-pole circuit breaker 66 is provided with aterminal strap 85 to which the respective stab terminal 68 is secured bya screw 86 extending through a reinforcing plate 87 and the terminalstrap 85 and threaded into an opening in the stab terminal 68.

The cover 70 is provided with three apertures 70a for respectivelyreceiving the stab terminals 68. The circuit breaker 66 is provided witha bracket and driving cam device similar to that disclosed in copendingapplication, Ser. No. 802,102, filed Feb. 25, 1969, and assigned to theassignee of this application. Thus, a bracket 88 secured to the circuitbreaker 66 rotatably supports a driving pin 90 having a cylindrical cam91 and an indicating plate 92 keyed thereto for rotation therewith.

The cover 70 is provided with a recess 70b surrounded by a frame member94 secured to the cover 70 by a plurality of screws 95. If desired, thescrews 83 may each be provided with a fiber washer 96 to retain thescrews 83 in assembled relationship with the cover 82 when it is removedfrom the cover 70 to provide access to the clamping screws 80.

In the installation of the circuit breaker 66, the cam 91 is received inthe recess 70b as the stab terminals 68 are received by the connector 36respectively through the apertures 70a. The drive pin 90 may then beturned in one direction with a hexagonal socket wrench to turn the cam91 which bears against the frame member 94 to move the circuit breaker66 parallel to the mounting pan 24 to plug the stab terminals 68respectively into the jaw members 76 and to plug the line-side jaws (notshown), as disclosed in U.S. Pat. No. 3,346,777, respectively onto thebus bars 26. The drive pin 90 may be turned in an opposite direction todisengage the circuit breaker 66 from the bus bars 26 and jaw member 76.

The circuit breakers 37 and 66 may be installed in or removed from theelectrical panelboard 20 without disturbing load wires (not shown)clamped respectively to the terminal straps 44 and 74 of the connectors35 and 36 by clamping screws 50 and 80.

In actual practice, more wiring space may be provided in an electricalpanelboard than is shown in FIG. 1 between the connector 36 and theadjacent sidewall of the box 22.

lclaim:

1. An electrical panelboard and circuit breaker combination comprisingan electric circuit breaker including an elongated generally rectangularmolded case, plug-on jaw line terminal means accessible from one endportion of the case longitudinally thereof, and plug-in load terminalmeans extending from a rear portion of the case adjacent the other endportion transversely of the direction of access of the plug-in lineterminal means, and an electrical panelboard including box having a rearwall, an elongated bus bar secured in the box in spaced parallelrelationship to the rear wall, and a plug-in load-side connector securedin the box in spaced relationship to the bus bar in a direction parallelto the rear wall, the plugin load-side connector including electricallyinterconnected load wire receiving terminal means and circuit breakerreceiving plug-in terminal means, and the circuit breaker receivingplug-in terminal means facing in a direction parallel to the rear walland away from the bus bar and electrically engaging the circuit breakerplug-in load terminal means upon movement of the circuit breaker in adirection parallel to the rear wall toward the bus bar and plugging ofthe circuit breaker plug-on jaw line terminal means on the bus bar.

2. An electrical panelboard and circuit breaker combination as claimedin claim 1 including a mounting pan secured to the rear wall of the boxand wherein the plug-in load-side con nector is secured to the mountingpan as a separate unit and includes a base having a compartment thereinand a cover secured to the base, the load wire receiving terminal meansand the circuit breaker receiving plug-in terminal means being disposedin the compartment in the base and the cover having a slot thereinproviding access to the terminal means in the compartment.

3. An electrical panelboard and circuit breaker combination as claimedin claim 1 and wherein the circuit breaker and the plugein load-sideconnector are provided with cooperative racking means for racking thecircuit breaker to plug and unplug the line terminal means respectivelyon and otT the bus bar and to plug and unplug the load terminal meansrespectively in and out of the circuit breaker receiving plug-interminal means.

4. An electrical panelboard andcircuit breaker combination as claimed inclaim 1 wherein the plug-in load-side connector includes a generallyL-shaped terminal strap, the load wire receiving terminal means issecured to one leg portion of the terminal strap, and the circuitbreaker receiving plug-in terminal means is a plug-in jaw member securedto the other leg portion of the terminal strap.

5. An electrical panelboard and circuit breaker combination as claimedin claim 1 wherein the circuit breaker includes three plug-on jaw lineterminal means accessible from the one end portion of the caselongitudinally thereof and three plugin load terminal means extendingfrom the rear portion of the case adjacent the other end portion, theelectrical panelboard includes three bus bars parallel to and alignedwith each other and spaced successively greater distances from the rearwall, and the plug-in load-side connector includes a case having threecompartments, three load wire receiving terminal means, and threecircuit breaker receiving plug-in terminal means, each of the threecompartments having one load wire receiving terminal means and onecircuit breaker receiving plug-in terminal means disposed therein.

6. An electrical panelboard and circuit breaker combination 5 as claimedin claim 5 wherein the case includes a base and a cover and the baseincludes two intermediate walls dividing the interior of the case intothe three compartments, and a rack member is mounted in one of theintermediate walls.

7. An electrical panelboard. and circuit breaker combination as claimedin claim 6 including a stop screw mounted in the other of theintermediate walls.

8. An electrical panelboard and circuit breaker combination as claimedin claim 5 wherein the circuit breaker has a driving cam mountedthereon, the case includes a base and a cover, and the cover has arecess for receiving the driving cam.

9. An electrical panelboard and circuit breaker combination as claimedin claim 8 including a frame member mounted on the cover, partiallylining the recess, and having a pair of opposed bearing surfacesengageable by the driving cam.

1. An electrical panelboard and circuit breaker combination comprisingan electric circuit breaker including an elongated generally rectangularmolded case, plug-on jaw line terminal means accessible from one endportion of the case longitudinally thereof, and plug-in load terminalmeans extending from a rear portion of the case adjacent the other endportion transversely of the direction of access of the plug-in lineterminal means, and an electrical panelboard including box having a rearwall, an elongated bus bar secured in the box in spaced parallelrelationship to the rear wall, and a plug-in load-side connector securedin the box in spaced relationship to the bus bar in a direction parallelto the rear wall, the plug-in load-side connector including electricallyinterconnected load wire receiving terminal means and circuit breakerreceiving plug-in terminal means, and the circuit breaker receivingplug-in terminal means facing in a direction parallel to the rear walland away from the bus bar and electrically engaging the circuit breakerplug-in load terminal means upon movement of the circuit breaker in adirection parallel to the rear wall toward the bus bar and plugging ofthe circuit breaker plug-on jaw line terminal means on the bus bar. 2.An electrical panelboard and circuit breaker combination as claimed inclaim 1 including a mounting pan secured to the rear wall of the box andwherein the plug-in load-side connector is secured to the mounting panas a separate unit and includes a base having a compartment therein anda cover secured to the base, the load wire receiving terminal means andthe circuit breaker receiving plug-in terminal means being disposed inthe compartment in the base and the cover having a slot thereinproviding access to the terminal means in the compartment.
 3. Anelectrical panelboard and circuit breaker combination as claimed inclaim 1 and wherein the circuit breaker and the plug-in load-sideconnector are provided with cooperative racking means for racking thecircuit breaker to plug and unplug the line terminal means respectivelyon and off the bus bar and to plug and unplug the load terminal meansrespectively in and out of the circuit breaker receiving plug-interminal means.
 4. An electrical panelboard and circuit breakercombination as claimed in claim 1 wherein the plug-in load-sideconnector includes a generally L-shaped terminal strap, the load wirereceiving terminal means is secured to one leg portion of the terminalstrap, and the circuit breaker receiving plug-in terminal means is aplug-in jaw member secured to the other leg portion of the terminalstrap.
 5. An electrical panelboard and circuit breaker combination asclaimed in claim 1 wherein the circuit breaker includes three plug-onjaw line terminal means accessible from the one end portion of the caselongitudinally thereof and three plug-in load terminal means extendingfrom the rear portion of the case adjacent the other end portion, theelectrical panelboard includes three bus bars parallel to and alignedwith each other and spaced successively greater distances from the rearwall, and the plug-in load-side connector includes a case having threecompartments, three load wire receiving terminal means, and threecircuit breaker receiving plug-in terminal means, each of the threecompartments having one load wire receiving terminal means and onecircuit breaker receiving plug-in terminal means disposed therein.
 6. Anelectrical panelboard and circuit breaker combination 5 as claimed inclaim 5 wherein the case includes a base and a cover and the baseincludes two intermediate walls dividing the interior of the case intothe three compartments, and a rack member is mounted in one of theintermediate walls.
 7. An electrical panelboard aNd circuit breakercombination as claimed in claim 6 including a stop screw mounted in theother of the intermediate walls.
 8. An electrical panelboard and circuitbreaker combination as claimed in claim 5 wherein the circuit breakerhas a driving cam mounted thereon, the case includes a base and a cover,and the cover has a recess for receiving the driving cam.
 9. Anelectrical panelboard and circuit breaker combination as claimed inclaim 8 including a frame member mounted on the cover, partially liningthe recess, and having a pair of opposed bearing surfaces engageable bythe driving cam.